Fig. 1: Identification of myogenic and mesenchymal stem cell/progenitor populations from mouse lemur skeletal muscle.

a Brightfield images of mouse lemur myogenic cells in proliferation (top panel) or differentiation (bottom panel) medium. Myogenic cells were obtained by pre-plating on plastic and grown on collagen-coated dishes. b, c UMAP plot of 10X single cell RNAseq data. Colors reflect the two replicates (b) or the different cell types (c). d UMAP plot as in (b, c), but now with MYF5-positive cells (top) or PDGFRA-positive cells (bottom) highlighted. e UMAP plot as in (b), but with NCAM1-positive cells (top) or THY1-positive cells (bottom) highlighted. f FACS plots for anti-NCAM1 and anti-THY1 staining (top) or no antibody control (bottom). g Muscle cryosections from indicated species were stained for PAX7 and counterstained for DAPI and WGA. Arrowheads mark PAX7⁺ nuclei in the MuSC position under the basal lamina. h Muscle cryosections from mouse, mouse lemur, and humans were stained for PDGFRα and counterstained for DAPI and WGA. Arrowheads mark interstitial PDGFRα⁺ cells. i Cells were grown from a single NCAM1⁺THY1⁻ cell isolated by FACS. Cells were grown in high serum (top) or in low serum (bottom). j Myoclone-derived myotubes were stained for MYH2 protein. k NCAM1⁻THY1⁺ cells were expanded for 7 days before treatment with indicated differentiation media. Cells were stained with Oil Red O, Wheat Germ Agglutinin, or Alizarin Red, respectively. Insets are magnified views of areas noted by the boxes. l Bioluminescence imaging (BLI) post-transplantation. Presumptive MuSCs (NCAM1⁺THY1⁻) were purified by FACS, transduced with a lentivirus expressing GFP and Luciferase, and transplanted into the TA muscles of NSG recipient mice. n = 17 from 3 donors. Mice were imaged over time and normalized BLI signal was plotted as the mean plus standard error. m BLI after secondary transplantation. Engrafted MuSCs following transplantation (as in (l)) were purified by FACS and transplanted into the TA muscles of an irradiated NSG mouse. n = 3 from 3 donors. MuSC transplantation was followed by bioluminescence imaging and compared to control mice (irradiated, injured, but not transplanted). Image of BLI is shown on top. Data are presented as mean values ± SEM. The p-value was calculated by unpaired, two-tailed Student’s t-test (*p < 0.05, p = 0.0388). Source data are provided as a Source Data file.